We know strikingly little about the core affective processes that drive the development and maintenance of, and recovery from anorexia nervosa (AN). To partially address this knowledge gap, we measured implicit and explicit affect toward pleasant, neutral, unpleasant, food-relevant, and weight-relevant images in three groups: in patients with acute AN, individuals recovered from AN, and healthy controls with no history of AN. Compared with the other two groups, acutely ill AN participants displayed significantly greater implicit positive affect toward pleasant images and significantly greater implicit negative affect toward unpleasant, high-calorie food, and overweight body type images. Recovered participants did not differ significantly from controls on any implicit affect measure. Explicit affective patterns were similar to implicit, but explicit measures yielded much smaller effect sizes and failed to detect certain group differences. Overall, negative implicit affect toward high-calorie foods and overweight body types may represent core affective processes that are operative during acute AN.
Affective processes such as fear of fat and drive for thinness are motivating features of anorexia nervosa (AN) (Habermas, 1996 and Steinglass et al., 2007), and are typically measured via explicit self-report which is vulnerable to biases such as lack of insight, motivation to conceal, and adherence to social norms (Konstantakopoulos et al., 2011 and Nisbett and Wilson, 1977).
Implicit measures that avoid these complications (Gawronski & Bodenhausen, 2006) reveal a bias against overweight- and toward underweight-related stimuli in AN patients; however, most studies yield only small to moderate effect sizes, fail to provide information about underlying affective processes, and rely on reaction time (Cserjesi et al., 2010 and Woud et al., 2011), which may be compromised by executive functioning deficits in AN (Green et al., 1996 and Zakzanis et al., 2010).
The Affect Misattribution Procedure (AMP; Payne, Cheng, Govorun, & Stewart, 2005), a computer-based measure of implicit affect, is reliable (Cronbach's alphas .8–.9), powerful (Cohen's d > 1.0), and specific to affective valence ( Payne et al., 2005). The AMP indexes automatic affective reactions (i.e., implicit affect) to stimuli that are minimally impacted by explicit self-report processes (c.f. Gawronski & Bodenhausen, 2006). Social pressure and motivation to conceal do not affect performance ( Payne, Govorun, & Arbuckle, 2008).
We used AMP to examine affective processes in AN toward emotionally-valenced and AN-specific stimuli. We hypothesized that AN patients would display significantly more negative responses to overweight and high-calorie stimuli, and significantly more positive responses to underweight and low-calorie stimuli.
